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Kuwait DGCA CPL Theory study materials
Kuwait DGCA CPL Theory study resources

Kuwait DGCA CPL Theory practice questions

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Question 1Air Law and ATC Procedures

Under ICAO Annex 1, what is the minimum age for the issue of a Commercial Pilot Licence?

  1. 21 years
  2. 16 years
  3. 18 years Correct answer.
  4. 17 years

Explanation

ICAO Annex 1 sets 18 years as the minimum age for a CPL applicant, while 17 years applies to the PPL and 16 years to the student pilot licence. Kuwait DGCA adopts this standard in its national licensing requirements.

Question 2Air Law and ATC Procedures

In Kuwait, which authority is responsible for issuing and renewing pilot licences and for approving ATC procedures at civil aerodromes?

  1. The International Civil Aviation Organization
  2. The Ministry of Defence
  3. The Directorate General of Civil Aviation Correct answer.
  4. The Kuwait Ports Authority

Explanation

The Directorate General of Civil Aviation (DGCA) is Kuwait's civil aviation regulator and is responsible for licensing personnel and overseeing civil air navigation services. ICAO sets standards but does not issue national licences.

Question 3Air Law and ATC Procedures

What is the standard vertical separation minimum applied between aircraft operating in controlled airspace above FL 290 in RVSM airspace?

  1. 1000 ft Correct answer.
  2. 500 ft
  3. 2000 ft
  4. 4000 ft

Explanation

Within designated RVSM airspace, the vertical separation minimum is reduced to 1000 ft between aircraft that meet RVSM approval. Above FL 410 or outside RVSM airspace, 2000 ft applies.

Question 4Air Law and ATC Procedures

An aircraft is intercepted by a military aircraft. According to ICAO Annex 2, what should the intercepted aircraft do first?

  1. Follow the intercepting aircraft's instructions and acknowledge by rocking wings Correct answer.
  2. Turn 180 degrees and accelerate away
  3. Switch off the transponder to avoid identification
  4. Immediately descend below the intercepting aircraft

Explanation

Annex 2 requires the intercepted aircraft to follow the intercepting aircraft's instructions, acknowledge by rocking wings, and attempt radio contact on the emergency frequency 121.5 MHz. It should not take evasive action unless instructed.

Question 5Air Law and ATC Procedures

Which transponder code should be selected to indicate a radio communication failure?

  1. 7600 Correct answer.
  2. 7000
  3. 7500
  4. 7700

Explanation

Code 7600 signals radio communication failure, 7500 signals unlawful interference and 7700 signals a general emergency. Code 7000 is the VFR conspicuity code in many regions.

Question 6Air Law and ATC Procedures

An aircraft on an IFR flight in controlled airspace experiences a two-way radio failure in VMC. What is the correct action?

  1. Continue under VFR and land at the nearest suitable aerodrome Correct answer.
  2. Descend immediately to the minimum safe altitude
  3. Climb to the highest available level and hold
  4. Return to the departure aerodrome at once

Explanation

Under Annex 2, an aircraft in VMC during a communication failure should continue to fly in VMC, land at the nearest suitable aerodrome and report its arrival by the most expeditious means. This avoids conflict with IFR traffic.

Question 7Air Law and ATC Procedures

What is the meaning of a red light signal directed at an aircraft on the ground from an ATC tower?

  1. Cleared for take-off
  2. Return to starting point
  3. Stop Correct answer.
  4. Cleared to taxi

Explanation

A steady red light directed at an aircraft on the ground means stop. A flashing red light means taxi clear of the landing area, while a green light means cleared for take-off or to taxi.

Question 8Air Law and ATC Procedures

In the ICAO phonetic alphabet, which word represents the letter Q?

  1. Queen
  2. Quota
  3. Quilt
  4. Quebec Correct answer.

Explanation

The ICAO spelling alphabet uses Quebec for Q, ensuring unambiguous radio communication between pilots and ATC. Standard words are fixed and must not be substituted.

Question 9Air Law and ATC Procedures

A pilot reads back a clearance and ATC responds 'readback correct'. What is the significance of this phrase?

  1. ATC has cancelled the clearance
  2. ATC confirms the readback matches the clearance issued Correct answer.
  3. ATC requires the pilot to read back again
  4. ATC is requesting the pilot's position

Explanation

'Readback correct' confirms that the pilot's readback accurately reflects the clearance, completing the loop required by Annex 10. It does not alter or cancel the clearance.

Question 10Air Law and ATC Procedures

An aircraft is cleared to 'hold at ABC VOR, inbound track 090, right turns, 4000 ft, expect further clearance at 1215'. What does 'right turns' specify?

  1. The direction to turn after leaving the hold
  2. The turn to be made after take-off
  3. The aircraft's heading on entry
  4. The direction of turn in the holding pattern Correct answer.

Explanation

The holding clearance specifies the turn direction within the pattern; 'right turns' means standard right-hand turns are made during the hold. It does not refer to headings on entry or after leaving.

Question 11Air Law and ATC Procedures

What is the purpose of a Standard Instrument Departure (SID) procedure?

  1. To specify the approach minima at the destination
  2. To provide obstacle clearance and ATC separation from the departure runway to a defined point Correct answer.
  3. To define the cruise altitude for the flight
  4. To establish the holding pattern at the destination

Explanation

A SID provides a published route from the runway to a designated point, ensuring obstacle clearance and allowing ATC to predict aircraft tracks. It does not define cruise levels or destination procedures.

Question 12Air Law and ATC Procedures

What does the abbreviation ATIS stand for in aviation communications?

  1. Approach Traffic Integration Service
  2. Air Traffic Information System
  3. Automatic Terminal Information Service Correct answer.
  4. Aeronautical Terminal Interface Standard

Explanation

ATIS is the Automatic Terminal Information Service, a continuous broadcast of recorded non-control information such as weather and runway in use. Pilots include the ATIS identifier in their initial call.

Question 13Air Law and ATC Procedures

An aircraft is on final approach and receives a 'go around' instruction from the tower. What should the pilot do?

  1. Reduce speed and continue to minima
  2. Apply go-around power, climb and follow ATC instructions Correct answer.
  3. Continue the approach and land
  4. Hold position on the runway

Explanation

A go-around instruction requires the pilot to abandon the approach, apply power, climb and follow the missed approach or ATC instructions. Continuing to land would conflict with the instruction and compromise safety.

Question 14Air Law and ATC Procedures

Under ICAO Annex 2, what is the minimum flight visibility for VFR flight at or below 900 m AMSL in Class C airspace?

  1. 1500 m
  2. 5000 m Correct answer.
  3. 300 m
  4. 8000 m

Explanation

In Class C airspace at or below 900 m AMSL, VFR flight requires flight visibility of at least 5000 m and distance from cloud of 1500 m horizontally and 300 m vertically. Lower minima apply only in Classes D, E, F and G where permitted.

Question 15Air Law and ATC Procedures

What does the term 'clearance limit' mean in an IFR clearance?

  1. The fuel required for the flight
  2. The point to which the aircraft is cleared Correct answer.
  3. The maximum altitude permitted
  4. The time by which the flight must land

Explanation

The clearance limit is the fix or point to which an IFR aircraft is cleared, beyond which further clearance is required. It is not an altitude, time or fuel limitation.

Question 16Air Law and ATC Procedures

An aircraft is instructed to 'squawk ident'. What is the expected pilot action?

  1. Turn off the transponder
  2. Switch to the emergency frequency
  3. Change to code 7700
  4. Press the ident button on the transponder Correct answer.

Explanation

'Squawk ident' instructs the pilot to activate the identification feature on the transponder, causing the radar return to be highlighted. It does not change the assigned code.

Question 17Air Law and ATC Procedures

Under ICAO Annex 13, what is the primary objective of an aircraft accident investigation?

  1. To determine insurance liability
  2. To determine the cause and prevent recurrence Correct answer.
  3. To apportion blame among crew members
  4. To prosecute the operator

Explanation

Annex 13 states the sole objective of an accident investigation is the prevention of accidents and incidents, not the apportionment of blame or liability. Findings are made without attributing fault.

Question 18Air Law and ATC Procedures

What is the standard emergency frequency for civil aviation and the associated distress signal?

  1. 121.5 MHz with MAYDAY Correct answer.
  2. 118.0 MHz with PAN PAN
  3. 122.0 MHz with MAYDAY
  4. 243.0 MHz with SECURITE

Explanation

121.5 MHz is the international aeronautical emergency frequency, and MAYDAY is the distress call indicating grave and imminent danger. 243.0 MHz is the military equivalent.

Question 19Air Law and ATC Procedures

What is the purpose of a runway holding position marking?

  1. To mark the touchdown zone
  2. To indicate where an aircraft must stop before entering a runway Correct answer.
  3. To indicate the taxiway centreline
  4. To show the displaced threshold

Explanation

Runway holding position markings indicate where aircraft must stop when clearance to enter the runway has not been given. They protect the runway strip from unauthorised entry.

Question 20Air Law and ATC Procedures

An aircraft is cleared to descend to 3000 ft. The pilot reports 'leaving 5000 ft for 3000 ft'. Which readback element is essential under Annex 10?

  1. The destination aerodrome
  2. The aircraft's registration
  3. The assigned altitude and the fact of leaving the previous level Correct answer.
  4. The pilot's name

Explanation

Annex 10 requires readback of altitude clearances, including the assigned level and, when leaving a level, the level being left. This ensures ATC knows the aircraft's vertical profile.

Question 21Aircraft General Knowledge: Airframe, Systems, Electrics, Powerplant and Emergency Equipment

On a light aircraft, what is the primary function of the empennage?

  1. To house the engine and absorb thrust loads
  2. To provide longitudinal and directional stability and control Correct answer.
  3. To store fuel and adjust the centre of gravity
  4. To carry the wing bending loads into the fuselage

Explanation

The empennage comprises the horizontal and vertical stabilisers together with the elevators and rudder. It provides longitudinal (pitch) and directional (yaw) stability and carries the control surfaces that give the pilot control about those axes. Wing bending loads are carried by the wing spar and fuselage attachments, not the tail.

Question 22Aircraft General Knowledge: Airframe, Systems, Electrics, Powerplant and Emergency Equipment

In a semi-monocoque fuselage, what is the role of the stringers?

  1. They carry the entire bending load without any skin contribution
  2. They form the pressure bulkheads at the nose and tail
  3. They stiffen the skin against buckling and carry part of the longitudinal loads Correct answer.
  4. They provide the attachment points for the landing gear only

Explanation

Semi-monocoque construction shares load between the skin and the internal framework. Stringers run lengthwise, stiffening the skin panels against buckling and carrying a share of the bending and shear loads together with the skin. The frames maintain the cross-sectional shape, and bulkheads close off pressurised compartments.

Question 23Aircraft General Knowledge: Airframe, Systems, Electrics, Powerplant and Emergency Equipment

A wing spar that is described as a 'box beam' derives its strength mainly from which feature?

  1. Upper and lower caps separated by two webs forming a closed torsion box Correct answer.
  2. A tubular strut running from wing root to fuselage
  3. A solid timber core with fabric covering
  4. A single deep web with no flanges

Explanation

A box spar uses upper and lower caps (booms) to resist bending and two webs to resist shear, joined so that the enclosed section also resists torsion efficiently. Separating the caps increases the second moment of area, which is why box spars give high stiffness for low weight.

Question 24Aircraft General Knowledge: Airframe, Systems, Electrics, Powerplant and Emergency Equipment

What is the purpose of a stall strip fitted on the leading edge of a wing?

  1. To prevent ice formation on the leading edge
  2. To increase the wing's maximum lift coefficient across the whole span
  3. To trigger an early, controlled stall at the wing root so ailerons remain effective Correct answer.
  4. To reduce the wing dihedral effect in turbulence

Explanation

A stall strip is a small sharp ridge placed near the wing root that disturbs the flow locally and causes that section to stall before the outboard sections. Because the ailerons stay unstalled, the pilot retains roll control and receives clear stall warning.

Question 25Aircraft General Knowledge: Airframe, Systems, Electrics, Powerplant and Emergency Equipment

In a manual flight control system, what is the function of a bell crank?

  1. To limit the maximum travel of the control column
  2. To convert linear cable movement into rotation and change the direction of the control force Correct answer.
  3. To provide artificial feel to the pilot
  4. To damp out flutter in the control surface

Explanation

A bell crank is a pivoted lever that redirects and transmits control forces through the linkage. Pulling one arm moves the other, converting cable tension into rotation at a new angle, which allows the routing of control runs around structure.

Question 26Aircraft General Knowledge: Airframe, Systems, Electrics, Powerplant and Emergency Equipment

An aircraft is fitted with a differential aileron linkage. What is the effect when the control wheel is turned to the right?

  1. Both ailerons move through equal angles in opposite directions
  2. The left aileron rises more than the right aileron falls, reducing adverse yaw Correct answer.
  3. Both ailerons move downward together to act as flaps
  4. The right aileron rises more than the left aileron falls, increasing adverse yaw

Explanation

Differential linkage gives the up-going aileron greater travel than the down-going one. On a right turn the left (up-going) aileron rises more, reducing the induced drag on the down-going wing and thereby reducing adverse yaw. This makes the turn smoother and reduces the rudder input required.

Question 27Aircraft General Knowledge: Airframe, Systems, Electrics, Powerplant and Emergency Equipment

What is the primary purpose of a hydraulic accumulator in an aircraft hydraulic system?

  1. To cool the hydraulic fluid after it leaves the pump
  2. To convert hydraulic pressure into electrical power
  3. To store pressurised fluid to absorb pressure surges and supply transient demands Correct answer.
  4. To filter contamination from the return line

Explanation

An accumulator contains a gas-charged chamber separated from the hydraulic fluid by a bladder, diaphragm or piston. It damps pressure pulsations from the pump, supplies fluid for short high-demand operations and maintains pressure for a limited time after pump failure.

Question 28Aircraft General Knowledge: Airframe, Systems, Electrics, Powerplant and Emergency Equipment

A hydraulic system reservoir is pressurised. What is the main reason for this?

  1. To increase the maximum system operating pressure
  2. To prevent pump cavitation and fluid foaming at high altitude Correct answer.
  3. To increase the viscosity of the fluid
  4. To allow the use of larger diameter pipes

Explanation

Pressurising the reservoir raises the fluid pressure at the pump inlet above the local ambient pressure. This suppresses cavitation and vapour lock at altitude and helps prevent foaming, ensuring the pump receives a solid supply of fluid.

Question 29Aircraft General Knowledge: Airframe, Systems, Electrics, Powerplant and Emergency Equipment

What is the function of a shuttle valve in a hydraulic system?

  1. To shut off the system when pressure exceeds a limit
  2. To alternate flow between two actuators at a fixed rate
  3. To remove air from the fluid during servicing
  4. To select the higher of two supply pressures and deliver it to a common outlet Correct answer.

Explanation

A shuttle valve has two inlets and one outlet; the higher-pressure source moves the shuttle and seals off the lower-pressure port. This allows, for example, a normal system and an emergency system to feed the same actuator without back-flow between them.

Question 30Aircraft General Knowledge: Airframe, Systems, Electrics, Powerplant and Emergency Equipment

In a typical light aircraft pneumatic system, what does the vacuum pump supply?

  1. Compressed air for engine starting
  2. Pressure for the fuel injection system
  3. Pressure to operate the landing gear
  4. Suction to drive the gyroscopic instruments Correct answer.

Explanation

Engine-driven vacuum pumps create suction that spins the gyros of the attitude indicator and directional gyro in a traditional flight instrument panel. Loss of suction causes these gyros to become unreliable, which is why a suction gauge is monitored.

Question 31Aircraft General Knowledge: Airframe, Systems, Electrics, Powerplant and Emergency Equipment

What is the purpose of a pressure relief valve in an aircraft hydraulic system?

  1. To prevent fluid from flowing backwards through the pump
  2. To limit system pressure by returning excess fluid to the reservoir Correct answer.
  3. To indicate system pressure in the cockpit
  4. To maintain a constant flow rate to the actuators

Explanation

A relief valve opens at a preset pressure and bypasses fluid back to the reservoir, protecting pipes, seals and components from overpressure. It is a safety device and normally remains closed during ordinary operation.

Question 32Aircraft General Knowledge: Airframe, Systems, Electrics, Powerplant and Emergency Equipment

In an aircraft DC electrical system, what is the purpose of a shunt?

  1. To provide a low-resistance path for measuring current Correct answer.
  2. To protect the circuit from overvoltage
  3. To convert AC to DC
  4. To store electrical energy for emergency use

Explanation

A shunt is a calibrated low-resistance element placed in series with the load; the small voltage drop across it is proportional to the current and is displayed on an ammeter. It avoids carrying heavy current up to the cockpit instrument.

Question 33Aircraft General Knowledge: Airframe, Systems, Electrics, Powerplant and Emergency Equipment

What does the term 'bus bar' mean in an aircraft electrical system?

  1. A device that converts 28 V DC to 115 V AC
  2. A fuse that protects the main generator
  3. A common conductor to which several circuits are connected Correct answer.
  4. A mechanical support for the battery

Explanation

A bus bar is a conductive bar or strip that distributes power from a source to multiple circuits. Individual circuits are connected to the bus through their own protection, so a single source can feed many loads.

Question 34Aircraft General Knowledge: Airframe, Systems, Electrics, Powerplant and Emergency Equipment

Why is a starter-generator able to perform two functions on a turbine engine?

  1. Because it operates on AC when starting and DC when generating
  2. Because it is driven by the accessory gearbox in both modes
  3. Because it contains two separate machines in one housing
  4. Because it uses the same field windings and armature for motoring and for generating Correct answer.

Explanation

A starter-generator is a single DC machine whose windings are used in two modes. In starter mode it is fed from the battery or external power and acts as a motor to crank the engine; once the engine is running it is driven and acts as a generator.

Question 35Aircraft General Knowledge: Airframe, Systems, Electrics, Powerplant and Emergency Equipment

What is the function of a current limiter in a heavy-duty aircraft DC circuit?

  1. To reverse the polarity of the supply
  2. To smooth ripple in the DC output
  3. To regulate generator voltage
  4. To open the circuit on sustained overload and protect the cable Correct answer.

Explanation

A current limiter is a slow-acting protective device, similar in principle to a fuse, used on high-current circuits such as the main generator feeder. It opens on a sustained overload before the cable is damaged but tolerates normal transient currents.

Question 36Aircraft General Knowledge: Airframe, Systems, Electrics, Powerplant and Emergency Equipment

In a four-stroke reciprocating engine, what happens during the compression stroke?

  1. The intake valve is open and the piston moves downward
  2. Both valves are closed and the piston moves upward, raising pressure and temperature Correct answer.
  3. The exhaust valve is open and the piston moves upward
  4. The spark plug fires and the piston moves downward

Explanation

During compression both valves are closed and the piston travels upward, reducing the trapped charge volume. Pressure and temperature rise, preparing the mixture for ignition at or near top dead centre.

Question 37Aircraft General Knowledge: Airframe, Systems, Electrics, Powerplant and Emergency Equipment

What is valve overlap in a four-stroke engine?

  1. The distance the valve lifts off its seat
  2. The period when both intake and exhaust valves are open around top dead centre Correct answer.
  3. The angle at which the spark occurs before top dead centre
  4. The clearance between the rocker arm and the valve stem

Explanation

Valve overlap occurs near the end of the exhaust stroke and the start of the intake stroke, when both valves are momentarily open. It uses the inertia of the exhaust gas to help scavenge the cylinder and improves volumetric efficiency.

Question 38Aircraft General Knowledge: Airframe, Systems, Electrics, Powerplant and Emergency Equipment

What is the main purpose of a turbocharger on a light aircraft engine?

  1. To cool the oil during climb
  2. To use exhaust energy to compress intake air and maintain power at altitude Correct answer.
  3. To drive the propeller at a constant speed
  4. To reduce the compression ratio at high power

Explanation

A turbocharger uses exhaust gas energy to spin a turbine that drives a compressor in the intake. The compressed intake air maintains manifold pressure and therefore power as altitude increases and ambient density falls.

Question 39Aircraft General Knowledge: Airframe, Systems, Electrics, Powerplant and Emergency Equipment

What is the function of a wastegate in a turbocharged engine installation?

  1. To release crankcase pressure to atmosphere
  2. To control the oil supply to the turbocharger bearing
  3. To limit turbine speed and boost by bypassing exhaust gas around the turbine Correct answer.
  4. To dump excess fuel during overboost

Explanation

The wastegate is a valve that routes exhaust gas around the turbine wheel. By controlling how much gas bypasses the turbine, it regulates compressor speed and therefore the maximum manifold pressure, protecting the engine from overboost.

Question 40Aircraft General Knowledge: Airframe, Systems, Electrics, Powerplant and Emergency Equipment

What does the term 'critical altitude' mean for a turbocharged engine?

  1. The highest altitude at which the turbocharger can maintain a given manifold pressure Correct answer.
  2. The altitude at which the wastegate is fully closed on the ground
  3. The altitude at which the engine must be shut down
  4. The altitude at which the turbocharger first begins to operate

Explanation

Critical altitude is the highest altitude at which the turbocharger can still deliver the selected manifold pressure, with the wastegate fully closed. Above it the compressor reaches its limit and manifold pressure falls with further climb.

Question 41Aircraft General Knowledge: Airframe, Systems, Electrics, Powerplant and Emergency Equipment

What is the purpose of a fire detection loop in an engine compartment?

  1. To extinguish a fire automatically without pilot action
  2. To vent smoke overboard from the cabin
  3. To isolate the affected generator from the bus
  4. To sense a fire or overheat condition and warn the crew Correct answer.

Explanation

Fire detection loops, such as continuous sensing elements, respond to the temperature rise of a fire or overheat condition and trigger a warning in the cockpit. Extinguishing is a separate action carried out by the fire extinguishing system.

Question 42Aircraft General Knowledge: Airframe, Systems, Electrics, Powerplant and Emergency Equipment

A fire extinguisher bottle for an engine compartment is typically discharged by which means?

  1. A spring-loaded plunger operated by the pilot's control
  2. A hand pump in the cockpit
  3. Gravity feed from a bottle mounted above the engine
  4. A cartridge that pressurises the bottle and expels the agent Correct answer.

Explanation

Most aircraft fire bottles are discharged by a small explosive or gas cartridge that pressurises the container and forces the extinguishing agent through the distribution tubing to the compartment. The pilot's switch fires the cartridge electrically.

Question 43Aircraft General Knowledge: Airframe, Systems, Electrics, Powerplant and Emergency Equipment

What is the function of a smoke detector in the baggage compartment of a pressurised aircraft?

  1. To detect a rapid decompression
  2. To warn of a fire that may not be visible to the crew Correct answer.
  3. To monitor the temperature of the cargo heater
  4. To control the cabin pressure schedule

Explanation

A smoke detector in an unoccupied compartment provides early warning of a fire that the crew cannot see. It allows the crew to take action such as isolating electrical power or discharging an extinguisher before the fire becomes uncontrollable.

Question 44Aircraft General Knowledge: Airframe, Systems, Electrics, Powerplant and Emergency Equipment

What is the purpose of a fire shut-off valve in an engine fuel system?

  1. To prime the engine before start
  2. To stop fuel flow to the engine in the event of a fire or engine shutdown Correct answer.
  3. To transfer fuel between tanks
  4. To regulate fuel pressure at the injectors

Explanation

A fire shut-off valve isolates the engine fuel supply at the firewall or engine feed line. Closing it removes the fuel source during a fire and is part of the engine shutdown and fire drill.

Question 45Aircraft General Knowledge: Instrumentation

In a light aircraft piston engine, which instrument indicates the rotational speed of the crankshaft in revolutions per minute?

  1. Manifold pressure gauge
  2. Tachometer Correct answer.
  3. Oil pressure gauge
  4. Fuel flow indicator

Explanation

The tachometer is the instrument that displays engine crankshaft rotational speed, usually in RPM, and is the primary reference for setting take-off, climb and cruise power in a fixed-pitch propeller aircraft. Manifold pressure, oil pressure and fuel flow measure entirely different engine parameters.

Question 46Aircraft General Knowledge: Instrumentation

A pilot selects the fuel gauge selector to the left tank and the indicator reads zero while the aircraft is known to be fuelled. Which action is the most appropriate first response?

  1. Tap the instrument glass to free the pointer
  2. Cross-check with the other tank indication and confirm the selector position before flight Correct answer.
  3. Continue the flight and monitor the gauge in cruise
  4. Assume the gauge is serviceable and plan on the right tank only

Explanation

Fuel quantity indications must be cross-checked against other evidence, such as the opposite tank reading and the physical selector position, because a single faulty or mis-selected indication is not proof of fuel state. Tapping the glass or ignoring the discrepancy is unsafe practice.

Question 47Aircraft General Knowledge: Instrumentation

In a conventional pitot-static system, which instrument is connected to both the pitot pressure source and the static pressure source?

  1. Altimeter
  2. Vertical speed indicator
  3. Airspeed indicator Correct answer.
  4. Turn coordinator

Explanation

The airspeed indicator is the only standard pitot-static instrument that receives both total (pitot) pressure and static pressure, and it displays the difference between them as indicated airspeed. The altimeter and vertical speed indicator use static pressure alone.

Question 48Aircraft General Knowledge: Instrumentation

During a climb with the static source blocked, the airspeed indicator will behave in which way?

  1. It will over-read immediately and then remain fixed
  2. It will read progressively higher than the true airspeed
  3. It will under-read initially and then behave like an altimeter as altitude increases Correct answer.
  4. It will indicate zero throughout the climb

Explanation

With the static port blocked, trapped static pressure stays at the value present at blockage while the pitot pressure reflects actual speed, so the instrument under-reads as the aircraft climbs. As the aircraft rises the trapped static pressure becomes progressively higher than ambient, so the indication drifts upward like a crude altimeter.

Question 49Aircraft General Knowledge: Instrumentation

An altimeter set to the local QNH reads the elevation of the aerodrome when the aircraft is on the ground. Which pressure is QNH?

  1. Pressure at the standard datum of 1013.25 hPa
  2. Station pressure reduced to mean sea level using the standard atmosphere Correct answer.
  3. Pressure corrected to the aerodrome mid-point temperature
  4. Actual pressure at the aerodrome reference point

Explanation

QNH is the aerodrome station pressure reduced to mean sea level using the standard atmosphere, so that an altimeter on the ground at that aerodrome indicates its elevation. QFE is the setting that reads zero on the aerodrome, and 1013.25 hPa is the standard pressure setting used for flight levels.

Question 50Aircraft General Knowledge: Instrumentation

An aircraft flies from a region of high pressure into a region of low pressure without the altimeter sub-scale being updated. What is the effect on the true altitude of the aircraft?

  1. The altimeter over-reads by a fixed amount regardless of altitude
  2. The aircraft is lower than the altimeter indicates Correct answer.
  3. The aircraft is higher than the altimeter indicates
  4. The altimeter indication is unaffected

Explanation

The altimeter measures pressure and converts it to altitude using the set sub-scale. Flying into lower pressure without resetting the sub-scale makes the instrument over-read, so the aircraft is actually lower than the indicated altitude, which is a significant terrain-clearance hazard.